Phonograph-tone-arm connection.



J. MATSON.

I PHONOGRAPH TONE ARM CONNECTION.

APPLICATION FILED APR. 23. [9|].

Patented Oct. 23, 1917.

' which it swings horizontally.

JULIUS MATSON, 0F GLENWOOD, ILLINOIS, ASSIGNOB T0 STEG-ER & SONS PIANO MANUFACTURING COMPANY, OF STEGER, ILLINOIS, A CORPORATION OF ILLINOIS.

PI IONOGRAPH-TONE-ARM CONNECTION.

Specification of Letters Patent.

Patented oer. 2a, 1911:.

Original application filed October 14, 1916, Serial No. 125,554. Divided and this application filed April 23,

and now pending, for improvement in phonograph tone arm connections.

The purpose of the present invention is to provide an improved construction of the tone arm of a phonograph or talking machine and its mounting, particularly with respect to its connections for swinging overthe record and toward and from the record,

and for counter-balancing any excess of weight of the tone arm causing undue pressure of the stylus upon the record. It consists in the elements and features of construction shown and described as indicate in the claims.

In the drawings:

Figure 1 is a partly sectional side elevation of a portion of a phonograph comprising the tone arm and its mount, section being made axially with respect to the tone arm at the vertical plane of the axis about Fig. 2 is a' section at the Fig. 1.

liig. 3 is a detail side elevation of the elbow portion of the tone arm,'showing an exteriorly-accessible device for adjusting the tension of the counter-balancing spring It is known that for the most eflective-and perfect reproduction of-music, either vocal or instrumental, as well as for the most per-- feet reproduction of articulate sounds of the human voice, Whether in song or speech, the

line, 2-2, on I proper adjustment of the weight or pressure of the stylus upon the record to'the character of the record is essential, and that a poor reproduction results from either too great or too little weight or pressure of the stylus upon the record. The normal weight of the soundbox and tone arm pivoted for swinging vertically toward and from the record, when the pivot for such swinging movement is substantially at the. vertical Serial No. 163,787.

line of the pivotingot said arm for swinging horizontally over the record, is usually in excess of the weight necessary for producing the maximum desirable pressure upon the record; and for the purpose of otfsetting the necessary proportion of this weight, a counterpoising spring may be connected with the arm. In the structure'shown in the drawing, the construction for pivoting the tone arm for both its'swingingmovements comprises a plate, I, mounted upon the top of the table, 2, on which the record carrier is supported in a familiar manner not necessary to be shown 'or described, said plate forming the upper end of the Vertical throat or downwardly-extending portion of the sound conduit not further illustrated, and having therefore an aperture corresponding in diameter to that throat, which aperture is bridged by a spider, 1, at the center of which there is pivoted for turning horizontally a yoke, 3, to whose up-turne'd ends, 3, the tone arm is pivoted by means of conepointed pivot screws, 4, 4, set in through the tone arm at diametrically opposite points for engaging said up-standing lugsof the yoke. The yoke has a short arm, 4:", pro jecting off from the middle point of its length, to the end of which there is secured in any convenient mannerthe lower end of a fiat spring or spring bar, 5, which extends up within the downwardly extending elbow member of the tone .arm. In the tone arm a little above its pivot to the yoke there is mounted a rock shaft, 6, which extends out through thetone arm at one side, provided with an operating means, as for example the knob, 7, for rocking. it. Inside the tone arm the rock shaft has a' lever arm, 8, extending up in the same general direction as the spring, 5, and connected to the latter by a short link, 9. Outside the tone arm the rock shafthas an index and locking finger, 10, which extends up alongside the downwardly-extending member of the elbow of the tone arm close alongside the latter in position to play over a notched segment, 11, which is formed or mounted rigidly upon the side of the tone arm. This index finger or lever. 'arm has some elasticity so that it is adapt-ed to snap intoth'e notches'll 11 and '11, formed in the notched segment, and thereby lock the rock shaft at the position at which it may be rocked for tensioning the spring, 5, more or less according to the requirement for adapting it to compensate more or less of the weight .of the tone afrmso as to produce the proper amount of pressure of the stylus upon the record. In

practifie for various records on the market three egre'es of pressure are found adequate and the segment is therefore provided with three notches only, though a greater number'may-be provided if intermediate adjustments are found desirable. The knob or handle, 7, is preferably at the end of the index and locking finger, 10, so that the operator can use it to spring the finger, 10, out ofjits locking engagement with the segment Whose notches may therefore be made square shouldered for positive engagement of the locking finger.

I claim 1. In a phonograph, in combination with a tone arm, a supporting member to which the tone arm is pivoted for swinging vertically, a sound conduit member upon which said supporting member is pivotally mountfor turning horizontally; a spring secured to-said supporting member and extending transversely thereof Within the tone arm, and means mounted in the tone arm for conmeeting the remote end of the spring with the tone arm, said means being exteriorly accessible and movable in the tone arm for varying the tension of the spring.

"2. In a pl'ionograph, in' combination with a tone arm, a supporting member to which the tone arm is pivoted for swinging vertically, a. sound conduit member upon which said supporting member is pivotally mounted for turning horizontally; a spring attached at one end to the supporting member extending Within the tone arm transversely of the axis of the vertical swinging movement thereof; a rock shaft mounted in the tone arm having a lever arm extending ofl therefrom within the tone arm in the general direction in which the spring extends; a link connecting said lever arm to flu spring, the attack shaft having exteriorly of the tone arm -ed for turning horizontally; spring t tached at one end to the supporting member extending \vitlnn the tone arm transversely of the axis of the vertical, swinging movement thereof; a rock shaft mounted in the tone arm having a lever arm extending off therefrom within the tone arm in the general direction in which the spring extends;

a link connecting said lever arm to the spring; therock shaft being extended to the exterior of the tone arm; an index finger thereon outside the tone arm and means for securing the rock shaft at a plurality of positions indicated by the index Finger.

1. In a phonograph, in combination with tone arm, a supporting member to which the tone arm is pivoted for swinging vertically, a sound conduit member upon which said supporting member is pivotally mounted for turning horizontally; a spring attached at one end to the supporting member extending within the tone arm transversely of the axis of the vertical swinging movement thereof;'a rock shaft mounted in the tone arm having a lever arm extending off therefrom within the tone arm in the general direction in which the spring extends; a link connecting said lever arm to the spring, the rock shaft having exteriorly of the tone arm a lever arm and a notched segment on the exterior of the tone arm concentric with the rock shaft having a plurality of notches for engaging the lever arm with the rock shaft to lock the rock shaft at adjusted position.

In testimony whereof I have hereunto set inv hand at Qteger, Illinois, this 19 day of April, 1917.

' J. narson'. 

